Timing Characteristics of Large Area Picosecond

The LAPPD Collaboration was formed to develop ultrafast large-area imag-ing photodetectors based on new methods for fabricating microchannel plates (MCPs). In this paper we characterize the time response using a pulsed, sub-picosecond laser. We observe single-photoelectron time resolutions of a 20 cm x 20 cm MCP consistently below 70 picoseconds, spatial resolutions of roughly 500 microns, and median gains higher than 107. The RMS measured at one particular point on an LAPPD detector is 58 psec, with ± 1σ of 47 psec. The differential time resolution between the signal reaching the two ends of the delay line anode is measured to be 5.1 psec for large signals, with an asymptotic limit falling below 2 picoseconds as noise-over-signal approaches zero